Fuel distributing unit for diesel engines



Get. 8, 1935. L, Q KENWORTHY 2,016,503

FUEL DISTRIBUTING UNIT FOR DIESEL ENGINES Filed June 5, 1954 imire A INVENTOR N N 20 ,ILCKenwort/ey ATTORNEY Patented Oct. 8, 1935 UNITED STATES PATENT OFFICE FUEL DISTRIBUTING UNIT FOR nmsm.

ENGINES 12 Claims.

This invention relates to Diesel engines and particularly to the pumping and distributing of the fuel underpressure to the individual injection valves of the cylinders of the engine.

At present two systems are in use for the feeding of the fuel to these valves. One is by means of what is called a common rail, which uses a single pump delivering into and maintaining a high pressure in a single pipe or rail, from which the fuel is fed to each cylinder by a mechanically operated valve. This system while relatively simple has certain inherent objectionable features as is well known to Diesel engineers. The other system uses a separate injection pump for each cylinder and while it avoids the above objectionable features, it is considerably more-ex will fully appear by a perusal of the followingspecification and claims.

In the drawing similar characters of reference indicate corresponding parts in the several vie'ws: Figure 1 is atop plan view of my improved unit partly in section.

Figure 2 is a vertical section .on the line 2'2 of Figure 1.

Referring now more particularly to the characters of reference on the drawing, the numeral I denotes a valve block rigid with and depending.

centrally from which is a pump barrel 2. A

plunger 3 either of the variable or constant stroke type is slidable in the barrel and is reciprocated by a rotary cam 4 driven from the engine as is usual. The pump barrel is in communication with the fuel intake passage 5 opening to the barrel at the bottom end of the plunger stroke,

and each stroke of the plunger creates sufficient pressure to open the injection valves of the engine, which as usual are set to resist a predetermined pressure.

The top of the barrel communicates with a chamber 6 formed in the valve block, and preferably axially alined with the said barrel, from which chamber a number of passages l radiatethere being one passage for each cylinder of the engine. Certain of the passages are preferably disposedat different levels in the block so as to avoid undue crowding while enabling the central chamber 6 .to be quite small as is desirable. The passages are formed with annular valve seats 8 facing away from the central chamber and engaged by the inner ends of valve members 9 mounted in the passages and also of course disposed radially of the chamber and pump.

Passages ID are formed in the block and lead from adjacent the valve seats of the passages 1 v to the adjacent ends of conduits II which extend to the usual injection valves of the individual 10 cylinders.

Each valve is normally held closed by a suitable spring I2 whose resistance isconsiderably less than the pressure of the fuel in the pump barrel and chamber 6, and which is generated by the 15 reciprocations of the pump plunger. In fact these springs need only have suflicient pressure to assure the closing of the valves after the liquid pressure is relieved. Said springs may be'of any desired character, but for simplicity they are 20 shown as compression springssurrounding the valve stems beyond the point of connection of the passages ID with the passages 1 and bear at their ends against collars C on the valve stems and,

plugs P closing the outer ends of the passages 1 25 as plainly shown. These valves, beside their major function as hereinafter set forth also act as check valves to hold the fuel in the line be tween the injection valves and the valve block.

The stems of the valves project outwardly of 30 the sides of the block and are normally engaged by individual heavy springs 13 whose resistance or pressure, acting on the outer ends of the valve stems to hold the valves closed, is appreciably greater than the pressurenecessary to open the injection valves and of the f'uelac'ting to open said injection valves and also the valves 9. If for instance the fuel pressure necessary to open the injection valves is 1800 lbs, the springs l 3 are set to resist a pressure up to 2400 lbs. or thereabouts, so that there is no possibility of any injection valve or valve 9 being opened unless its holding spring 13 is positively released. The springs 13 are preferably of the lead type being secured at one end on the block I to one side of the respective valve stems and bearing at their free endsagainst the outer ends of said stems. 5

To withdraw each spring l3 in turn from the valve stem with which it cooperates, so as to allow the liquid pressure in the chamber 6 to open such valve, I provide the following means:

Tur'nable on the pump barrel and of course concentric therewith just below the block I is a gear '4 having a single outwardly projecting cam I5 on its periphery above the gear teeth. 5

This cam with the rotation of the gear is adapted to successively engage rollers l6 mounted on the lower ends of arms H and force the adjacent ends of said arms outwardly. These arms project between the springs l3 and the block and are pivoted at their upper ends on cars I8 mounted on top of the block. The arms and cam are arranged so that when the cam is fully engaged with any arm, the corresponding spring i3 is moved sufificiently away from the adjacent valve stem to allow the latter to move to a wide open position without contacting said spring. It will therefore be clear that only one of all the valves can open at any one time, such valve being the one with the least resistance thereon or that one whose spring l 3 has been lifted from contact with the valve stem. The injection valves of the engine have a given tension, which is less than that of the spring 63, so that when any such spring is lifted and the tension on the corresponding valve stem is removed, the fuel forced into the chamber 8 by the operation of the pump passes to the corresponding injection valve and into the engine.

- The cam gear is rotated once for each four reciprocations of the pump plunger (in the four valve type of unit here shown) and this can be done in any convenient manner, such as by suitable gearing connections, as indicated at B9, between the gear i l and the pump operating cam shaft 20. The cam i5 is timed to raise a spring 5 3 as the pump plunger is on its pressure stroke, so as to allow the fuel pressure to open the corresponding valve; and to relieve the spring at any time after the pump plunger starts on its succeeding downward stroke, since the auxiliary springs 20 are sufiiciently strong to close the valves when the liquid pressure thereon is relieved.

It is to be noted that it is not necessary for the pressure or tension of all the springs E3 to be the same, since all such springs are mechanically and positively raised against their pressure irrespective of the liquid pressure, and as long as the spring pressure is appreciably in excess of the liquid pressure, variations in pressure between the springs themselves or in the pressure difference between said springs and the liquid is immaterial. This is also true of the springs i2. The manufacturing problems are therefore greatly simplified over what is necessary with present equipment, since no attention need be paid in getting these springs to be exact duplicates of each other for the reasons above stated.

From the foregoing description it will be readily seen that I have produced such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described my invention what I claim as new and useful and desire to secure by Letters Patent is:

l. A fuel distributing unit for Diesel engines comprising a block having a fuel chamber therein, and a plurality of separate branch passages leading from the chamber and adapted for con nection to the individual injection valve devices of an engine, means to intermittently force fuel into the chamber at a certain pressure, valves closing the branch passages and adapted to be opened by the fuel pressure in said chamber, means normally holding said valves closed with a pressure greater than that of the fuel, and means to positively release the holding means of the several valves only one at a time and only during successive pressure strokes of the fuel forcing means.

2. A fuel distributing unit for Diesel engines comprising a block having a fuel chamber therein, and a plurality of separate branch passages leading from the chamber and adapted for connection to the individual injection valve devices of an engine, means to intermittently pump fuel into the chamber at a certain pressure, valves closing the branch passages and adapted to be opened by the fuel pressure in said chamber, means normally and separately holding the valves closed with a pressure greater than that of the fuel, and mechanic-a1 means functioning in timed relation to and only during the pressure strokes of 20 the pumping means to release the holding means of the valves in predetermined successive order.

3. A fuel distributing unit for Diesel engines comprising-a block-having a fuel chamber therein, and a plurality of separate branch passages 25 leading from the chamber and adapted for connection to the individual injection valve devices of an engine, intermittently operating means to force fuel into the chamber at a certain pressure, valves closing the branch passages and adapted to be opened by the fuel pressure in said chamber, springs acting individually on the several valves to hold the same closed with a pressure greater than that of the fuel, and positive mechanical means to relieve the pressure of the springs one at a time in predetermined order and only during successive pressure strokes of the fuel forcing means whereby the fuel pressure will open the valve whose spring is then relieved.

4. A fuel distributing unit for Diesel engines comprising a block having a central enclosed fuel chamber, and a plurality of passages radiating from said chamber and adapted for connection to the individual fuel, injection devices of an engine, means to force fuel into said chamber at a certain pressure, annular valve seats formed in said passages, valves slidable in the passages engaging the seats and opening away from the chamber whereby the fuel pressure therein will tend to open the valves, stems on the valves projecting to the outside of the block, springs engaging the outer ends of the stems and forcing the valves closed with a pressure greater than that of the fuel in the chamber, and means to successively withdraw the springs from the valve stems.

5. A structure as in claim 4 in which said last named means includes a rotary driven cam member mounted on the block in axial alinement with the point of axial intersection of the radiating passages.

6. A structure as in claim 3, with additional springs acting on the valves to close the same and having an effective pressure less than that of the fuel in the chamber.

'7. A fuel distributing unit for Diesel engines comprising a block having an enclosed fuel chamber, and a plurality of passages leading from said chamber and adapted for connection to the individual fuel injection devices of an engine, means to force fuel into said chamber at a certain pressure, annular valve seats formed in said passages, valves slidable in the passages engaging the seats and opening away from the chamber whereby the fuel pressure therein will tend to open the valves, stems on the valves projecting to the outside of the block, leaf springs, one for each valve stem, each mountedat one end on the block and adjacent its opposite end engaging the outer end of a valve stem, and mechanical means mounted on the block for moving the springs clear of the corresponding valve stems in predetermined order.

8. A fuel distributing unit for Diesel engines comprising a block having a fuel chamber therein. and a plurality of separate branch passages leading from the chamber, a fuel pump barrel depending from the block and communicating with the chamber, said passages extending radially of the axis of the barrel, a pump plunger slidable in the barrel, valves in said passages to close the same adjacent their inner ends and opening away from the chamber, conduits connected to the passages beyond the point of closure and adapted to extend to the injection valve devices of an engine, stems on the valves projecting outwardly of the periphery of the block, springs engaging said stemsto hold the valves closed with a pressure greater than that imparted to the fuel by the pump plunger, movable elements engaging said springs and adapted when moved to withdraw the springs from engagement with the valve stems, means to thus successively move the elements comprising a single-point cam turnably mounted on the barrel concentric therewith, means to reciprocate the plunger, and connecting means between the cam member and said reciprocating means arranged so that with each complete revolution of the cam member, the plunger will be reciprocated as many times as there are valves.

9. A fuel distributing unit for Diesel engines comprising a block having a fuel chamber therein, and a plurality of separate branch passages leading from the chamber and adapted for connection to the individual injection valve devices of an engine, means to force fuel into the chamber at a certain pressure, and including a reciprocating-plunger pump, valves closing the branch passages and adapted to be opened by the fuel pressure in the chamber, releasable means normally holding the valves closed with a pressure greater than that of the fuel, means to positively release the holding means of the several valves one at a time, means to reciprocate the pump plunger, and connection means between the plunger reciprocating means and the releasing means to actuate the latter for any one valve once only during each pressure stroke of the plunger.

10. A fuel distributing unit for Diesel engines comprising a block having a fuel chamber therein, and a plurality of separate branch passages leading from the chamber and adapted for connection to the individual injection valve devices of an engine, means to force fuel into the chamber at a certain pressure, and including a reciprocating-plunger pump, valves closing the branch passages and adapted to be opened by the fuel pressure in the chamber, releasable means normally holdin the valves closed with a pressure greater than that of the fuel, means to reciprocate the plunger, and means functioning with each such reciprocation to release one only of the valve holding means, said last named means being arranged to release the holding means of the several valves in succession only during successive pressure strokes of the plunger.

11. In combination with a plurality of separate conduits adapted at one end for connection to the several fuel injection valves of a Diesel engine, check valves in said conduits opening toward the injection valves, means to intermittently force fuel into the conduits ahead of the valves with a pressure suflicient to open the injection valves, means holding the check valves closed with a pressure in excess of that of the fuel in the conduits, and means independent of such fuel pressure to release the holding means of the different check valves one at a time and only with successive pressure strokes of the fuel forcing means.

12. A fuel distributing unit for a Diesel engine comprising a block having an enclosed fuel chamber, a plurality of passages leading from said chamber for connection to the individual fuelinjection devices of an engine, means to force fuel into the passages at a certain pressure, valves in said passages opening away from the chamber, stems on the valves projecting to the outside of the passages and chamber springs engaging the outer ends of the stems and forcing the valves closed with a pressure greater than that of the fuel in the chamber, and means to successively withdraw the springs from pressing engagement with the stems.

LOUIE C. KENWORTHY. 

